Voltage reducing power electronic transformer for distribution network

Abstract

The invention discloses a voltage reducing power electronic transformer for a distribution network. Structures of single phases in a three-phase circuit are the same and independent; each phase comprises an input level, an isolation level and an output level; the input level of the single phase is formed by cascading a plurality of same power transformers to adapt high-voltage input, and the power transformer comprises an uncontrolled rectifier bridge and a boost-based power factor correction circuit; the isolation level comprises a high-frequency direct current (DC) / alternating current (AC) link, a high-frequency transformer and a high-frequency AC / DC link, and a parallel mode is adopted in the output level of an isolation level module of each phase to adapt a high-power load; and the output level consists of a three-phase voltage source converter of four bridge arms, three-path output can be realized according to the requirement of the load, and the converter of the output level is also connected with a liquid crystal (LC) filter to improve the waveform quality of the voltage and the current. The power electronic transformer can improve the conversion efficiency at the same time of reducing the production cost, improve the reliability of a device, adapt different load requirements of the distribution network and improve the flexibility in the use of the distribution network, and has good application prospect.

Description

technical field [0001] The invention relates to a power transmission and distribution device capable of realizing multiple functions, in particular to a step-down power electronic transformer for distribution network. Background technique [0002] Since its invention in the 19th century, power transformers have become the basic components of power transmission and distribution systems. Although the traditional power transformer has the advantages of simple manufacturing process and high reliability, it can only realize voltage level transformation and insulation isolation, and its function is relatively single. Moreover, due to the electromagnetic coupling between the primary and secondary sides of the transformer, it is impossible to realize fault current and voltage on both sides of the transformer. The isolation of faults limits the scope of faults; the isolation of distorted currents and interference voltages on both sides of the transformer cannot be achieved, which on ...

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Problems solved by technology

Although the traditional power transformer has the advantages of simple manufacturing process and high reliability, it can only realize voltage level conversion and insulation isolation, and its function is relatively single. Moreover, due to the electromagnetic coupling between the primary and secondary sides of the transformer, it is impossible to realize fault current and voltage on both sides of the transformer. The isolation of faults limits the scope of faults; the isolation of distorted currents and interference voltages on both sides of the transformer cannot be achieved. On the one hand, sensitive loads are affected, and on the other hand, the power grid is polluted; Circulation, insulating oil pollution and other issues

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